Functional Comparison Of TPS Genes In Flowers Of Aquilegia Japonica Nakai Et Hara And A. Amurensis Kom.

Floral scent is one of volatile organic compounds with low molecular weight,which is produced by plant floral organs.It plays an important role in the growth and reproduction of plants.It can not only attract pollinators,but also generate signals to attract the enemies of predators to resist biotic stresses.In addition,it is also a complex trait that mediates plantanimal interactions.Terpenoids are the main components of floral scents.The synthesis and release of terpenoids are of great significance for plants to adapt to complex and changeable environments.Previous studies analyze the floral scents composition of Aquilegia japonica Nakai et Hara and its sister species A.amurensis Kom.It is found that there are significant differences in the composition and content of monoterpenes and sesquiterpenes in the flowers of these two species.Terpene synthases(TPS)play an important role in the biosynthesis of volatile terpenoids.This study analyzed the differences of TPS genes in the flowers of A.japonica and A.amurensis,cloned the terpene synthase genes by molecular biology methods,identified the function of the encoded protein,and determined the subcellular localization.The main research results of this study are as follows:(1)Phylogenetic analysis was performed for 9 TPS genes in A.japonica and 13 TPS genes in A.amurensis.Accordingly,AjTPS2,AjTPS3,AjTPS4,AjTPS7,AjTPS8,AjTPS9,AaTPS2,AaTPS3,AaTPS4,AaTPS6,AaTPS7,AaTPS10,AaTPS11,AaTPS12 and AaTPS13 were TPS-b subfamily genes;AaTPS8 and AaTPS9 were TPS-c subfamily genes;AjTPS1,AjTPS5,AjTPS6,AaTPS1 and AaTPS5 were genes in the TPS-e/f subfamily.(2)AjTPS1 and AaTPS1 proteins were monoterpene synthases that catalyzed the production of linalool from GPP.AjTPS1 and AaTPS1 protein had 10 different amino acid,and their secondary structures were different.AaTPS1 protein catalyzed GPP to produce more linalool.(3)The protein sequences of AjTPS2 and AaTPS2 differed by 6 amino acids,and their functions were changed.AjTPS2 was a monoterpene synthase that catalyzed the production of linalool from GPP,while AaTPS2 was a sesquiterpene synthase that catalyzed the production of β-bisabolene,α-bisabolol and β-sesquiphellandrene from zz-FPP.(4)There were 3 amino acid mutations in the protein sequences of AjTPS3 and AaTPS3,and this difference was reflected in their secondary structures,but did not cause functional differences.AjTPS3 and AaTPS3 were sesquiterpene synthases that catalyzed the production of β-bisabolene,α-bisabolol and β-sesquiculene from zz-FPP.Subcellular localization showed that both of them were located in the chloroplast.Above study verifies the functions of three orthologous TPS genes in A.japonica and its sister species A.amurensis,and further reveals the molecular mechanism underlying the differences in floral scent composition between them,providing a reference for exploring the role of floral scent composition in the speciation and adaptive evolution of Aquilegia taxa.